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Rh Factor Incompatibility


  • Rhesus (REE-sus) factor, or Rh factor incompatibility happens when you are Rh negative and you are carrying an Rh positive baby. Rh factor is a protein found on red blood cells. You are Rh positive (Rh+) if you have this protein in your blood. You are Rh negative (Rh-) if you do not have it. When Rh positive blood mixes with your Rh negative blood, your body sees it as foreign and makes antibodies. Rh antibodies cross the placenta (tissue in the womb connecting the mother and baby) and attack your baby's blood. Your baby may develop anemia (low red blood cell count) or jaundice (yellowing of the skin or eyes).
  • Blood tests to check your blood type and if have Rh antibodies are needed to diagnose an Rh factor problem. The father should also have the same blood tests. Amniocentesis, ultrasound, or fetal blood sampling may also be needed to check for an Rh factor problem. The best way to treat an Rh factor problem is to have Rh immune globulin (RhIg) shots, which prevent antibodies from forming.


Take your medicine as directed:

Call your primary healthcare provider if you think your medicine is not helping or if you have side effects. Tell him if you are allergic to any medicine. Keep a list of the medicines, vitamins, and herbs you take. Include the amounts, and when and why you take them. Bring the list or the pill bottles to follow-up visits. Carry your medicine list with you in case of an emergency.

Ask for information about where and when to go for follow-up visits:

For continuing care, treatments, or home services, ask for more information.


  • You have a fever.
  • You have bad abdominal (stomach) pain.
  • You have questions or concerns about your condition, medicine, or care.


  • You feel your baby is moving less or is not moving at all.
  • You have trauma, especially to your abdomen (stomach), even if you do not feel like you were hurt.
  • You have heavy vaginal bleeding.

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Learn more about Rh Factor Incompatibility (Aftercare Instructions)

Associated drugs

IBM Watson Micromedex